A weather warning has been issued with up to 30mm of rain expected to fall in some areas on Saturday.
The 'status yellow' Met Éireann alert, the lowest of the three warning categories, was issued last night and will remain in place until midnight.
A series of heavy showers are expected to turn thundery in many areas during this afternoon and evening with the possibility of spot flooding.
“Tonight there will be further outbreaks of heavy rain in most areas, with a risk of thundery showers also”, the forecaster said in a statement.
Motorists have been urged to be careful.
Rain will ease over much of the country overnight and Sunday will be much milder with some bright or sunny spells. However there is a risk of further heavy showers.
The outlook for Bank Holiday Monday is a similar mix of showers and brief sunny spells.